In many sectors of engineering it is required to achieve as effective as possible a heat transfer between a tubular body conducting a fluid and a contact body that is in contact with said tubular body. For example, heat from the fluid is to be directed into the contact body or, conversely, heat is to be transferred from the contact body into the fluid and discharged. Thus, such heat transfer arrangements are applied for cooling or for heating of a contact body by means of a fluid flow. Here, it is possible in principle, that the contact body is likewise a fluid-conducting tube so that via the arrangement heat can ultimately be transferred from the one fluid into the other fluid.
With modern applications, thermoelectric converters or thermoelectric generators are employed which convert a temperature differential into a voltage differential or a heat flow into an electric current. Such thermoelectric generators operate according to the inverted Peltier effect and thus operate analogously to Peltier elements. In a heat transfer device such thermoelectric generators can now be arranged each between a warm tube, conducting a heat-emitting fluid and a cold tube conducting a heat-absorbing fluid. The temperature differential between warm tube and cold tube is then present at the respective thermoelectric converter and can be converted into electric current.
With all these applications it is required for realising as high as possible an efficiency of the heat transfer that a surface-to-surface contact is present between the respective tubular body and the respective contact body, namely over the entire temperature range to which the arrangement is subjected during regular operation. In order to guarantee the desired surface-to-surface contacting and in order to improve the heat transfer it is possible in principle to press the tubular body and the contact body together with the help of a preload force. It has been shown however that in the case of tubular bodies bulging frequently occurs when too large a preload force is selected. Through the bulging, the tubular body can lift off the contact body in certain regions so that the previously surface-to-surface contact to the contact body becomes strip-shaped or line-shaped, which substantially impairs the heat transfer. Added to this are heat expansion effects in the case of which the respective tubular body, the respective contact body as well as preloading means for generating the preload force can expand differently, as a result of which a change of the preload force can occur so that the bulging of the tubular body for example only occurs at higher temperatures.